Theoretical study of the characteristics of modulation noise in magnetic tapes.

The influence of surface roughness on modulation noise was studied theoretically using a simplified sinusoidal head-tape contact model. Co-γFe2O3 tapes having sinusoidal surface roughness were prepared, and their modulation noise was measured by VHS VTR. It was found that the modulation noise contained both amplitude modulation (AM) and phase modulation (PM) components; AM and PM noise increased with the increase in ratio of surface roughness to recording wavelength, and PM noise increased with the decrease in ratio of spatial wavelength of tape surface to recording wavelength.